C#通过n层循环进行字符组合实现暴力破解MD5

static class Program
{
    /// 

    /// 应用程序的主入口点。
    /// 
    [STAThread]
    static void Main()
    {
        string[] plainArray = "0,1,2,3,4,5,6,7,8,9";	//可疑字符串
        string cipherStr = "202CB962AC59075B964B07152D234B70";	// 待解密MD5字符串，32位
        //string cipherStr = "AC59075B964B0715";	// 待解密MD5字符串，16位
        int n = 6;	// 明文长度
        
        bool isDecried = false;
        string plainStr = MD5Decrypt(plainArray, n, cipherStr, ref isDecried);
        if (isDecried)
        {
        	Console.WriteLine(plainStr);
        }
        else
        {
        	Console.WriteLine("解密失败，明文不在可疑明文字符组合中！");
        }
    }
    
    /// 

    /// MD5解密
    /// 
    /// 可疑明文字符数组
    /// 明文长度
    /// 待解密的密文
    /// 是否已完成解密
    /// 解密后的明文
    private string MD5Decrypt(string[] plainArray, int n, string cipherStr, ref bool isDecried)
    {
        List<string[]> list = new List<string[]>();
        for (int i = 0; i < n; i++)
        {
            list.Add(plainArray);
        }
        string plainStr = "";
        MD5 md5 = MD5.Create();
        MD5Combination(0, list, md5, cipherStr, "", ref plainStr, ref isDecried);
        return plainStr;
    }
    
    /// 

    /// MD5解密（迭代实现 N 层字符组合，对组合字符串进行MD5后和密文进行比对）
    /// 
    /// N层明文字符串集合的索引
    /// N层明文字符串集合
    /// MD5对象，避免重复创建对象导致内存溢出
    /// 待解密的密文
    /// 组合字符串
    /// 解密后的明文
    /// 是否已完成解密
    private void MD5Combination(int index, List<string[]> matrix, MD5 md5, string cipherStr, string str, ref string plainStr, ref bool isDecried)
    {
        for (int k = 0; k < matrix[index].Length; ++k)
        {
            if (isDecried)
            {
                return;
            }
            string charStr = matrix[index][k];
            String tempStr = str + charStr;
            string encryStr = "";
            switch (cipherStr.Length)
            {
                case 16:
                    encryStr = BitConverter.ToString(md5.ComputeHash(Encoding.UTF8.GetBytes(tempStr)), 4, 8).Replace("-", "");
                    break;
                case 32:
                    encryStr = BitConverter.ToString(md5.ComputeHash(Encoding.UTF8.GetBytes(tempStr))).Replace("-", "");
                    break;
            }
            if (encryStr == cipherStr || encryStr.ToLower() == cipherStr)
            {
                plainStr = tempStr;
                isDecried = true;
                return;
            }
            else if (index < matrix.Count - 1)
            {
                MD5Combination(index + 1, matrix, md5, cipherStr, tempStr, ref plainStr, ref isDecried); // 向下传递的逻辑
            }
        }
        return;
    }
}